Rock-drilling engine.



A Patented luneI I2, |900. J. G. LEYNER.

ROCK DRILLING ENGINE.

(Application filed Apr. 29, 1899-) (No Model.)

Pnomumo. wAsmNGron, n4 c;

No. 65|,487. PatentennineA |2 |900.

J. G. LEYNER. ROCK DRILLING ENGINEQ` (Applicatie): filed Apr. 29, 1899.)(no Mom.) 4 shamsheet 2'.

No. 65|,4a7.

.L G. LEYNEB. ROCK DRILLING ENGINE.-

(Applicgzion med Apr. 2o, `1899.1

Patented' lune l2, |900.

(No Model.)

4 sham-sheet s.

No. 65|,487. Patenled'lune l2, |900. J. G. LEYNEH.

ROCK DRILLING ENGINE.

(Application led Apr. 29, 1899.)

4 Sheets-Sheet 4*.

(No M'qdel.)

v UNITED STATES.

'ATE* JOHN GnoRGi; LE'YNER, or DENVER, COLORADO.

ROCK-DRILLING' NGINE.

SPECIFICATION forming` part 0f Letters Patent N0. 651,487, dated. June12, 19O. Application tiled April 29, 1899. Serial No. 715,037. (Nomodel.)

To @ZZ whom 2125 may concern,.-

Be it known that I, JOHN GEORGE LEYNER,

a citizen of the United States of America, residing at Denver, in thecounty of Arapahoe and State of Colorado, have invented certain new anduseful Improvements in Rock-Drilling Engines; andl do declare thefollowing to be a full, clear, and exact description of the invention,such as will enable others skilled in the artto which it appertains tomakeand use the same, reference being had to the accompanying drawings,and to the letters and figures of reference marked thereon, which form apart of this specification.

My invention relates to improvements in air or steam rock-d rillin gengines adapted to expel rock cuttings from rocks while drilling them;and the objects of my invention are, first, to provide a rock-drillingengine that will discharge againstthe bottom of a hole while drilling ita jet of the engines actuating air or steam combined with a stream ofwater under pressure; second, to provide means for regulating the flowof the water; third, to provide means for conveying the water throughthe drilling-engineandits drill-bitandto thedrillbits cutting-point tothe bottom of the hole being drilled; fourth, to provide means foruniting the air and water in the shank ofthe drillbit; fifth, to providemeans for connecting the Water-supply to either side of the engine;sixth, to provide an operating rock-drilling engine in which thedrill-bit is stationary relative to the reciprocal movements of thepiston and is loosely and non-clampably supported by the drilling-engineand is arranged to be instantly withdrawn therefrom or inserted thereinat the will of the operator and that is adapted to be intermittentlyrotated step by step therein by the reciprocating and intermittentrotary movement of the piston and which is adapted to convey a portionof the pistons actuated fluid from the engines cylinder combined with ajet of water to the bottom of holes while drilling them, and, seventh,to'provide a rock-drilling engine adapted to drive the rock cuttingsfrom holes while drilling them and to lay the rock-d ust formed by the drill-bit while cuttingor drilling into rock. ism illustrated in theaccompanying dra'wings, in whichengine. Ition ofthe air-inlet Valve.size sectional view of the valve-chest.

I attain these objects by the mechan- 1 cross-section of Fig. 1 on lineA. Fig. 5 is a cross-section of Fig. l'on line B. Fig. 6 is across-section of Fig. 1 on line C. Fig. 7is a cross-section on line D.Fig. 8 isa cross-section of Fig. 1 online E. Fig. 9is an end elevationof the front or drill-bit holding end of the drilling-engine. Fig. 10 isan end elevation ofthe rear or -feed end of the drilling- Fig. 11 is anenlarged central sec- Fig. 13 is a full-size central plan View of thevalvechest. Fig. 14 is a cross-section of Figs. 12 and 13 on line F.Fig. 15 is a longitudinal sectional view of the main valve. Fig. 16 is across-section of Figs. 12 and 13 on line G. Fig.` 17 is a top plan viewof the cylinder-seat of the valve-chest. Fig. 18 isacross-section online H of Fig. 17. Fig. 19 is a cross-section on line I of Fig. 17. Fig.20 is a fragmentary sectional view of the valve-chests seat, showing afragment of the piston in the cylinder on line H A of Fig. 17. Fig. 21is a side elevation of the drill chuck-sleeve. Fig. 22 is an endelevation of the end K of Fig. 21. Fig. 23 is an end elevation of theend L of Fig. 21. Fig. 24 is a side elevation of the drills chuck. Fig.25 is an end elevation of the end M of Fig. 24. Fig. 26 is an endelevation of the end N of Fig. 24. Fig. 27 is an end elevation of thechuck-sleeve and the chuck, showing the oblong holes at right angles toeachother, in which the drill-bit rests. Fig. 28 is a side elevation ofthe chuck-bearing ring. Fig. 29 is a cross-section of Fig. 28 on line J.Fig. 30 is a side elevation of the ride-bar. Fig. 31 is an enlargedfragmentary sectional view of the water-tube and the shank of thedrill-bit. Fig. 32 is a section of Fig. 33 on line K, and Fig. 33 isaside elevation of the piston and its hammer-bar.

Similar letters and figures ofreference refer to similar partsthroughout the several views.

Referring to Fig. 1, D D designate the cylinder, E l.E the piston, F Fthe steamchest, G Gr the valve, H H the guide-shell,

Fig. 12 is a full;

IOO

in which the cylinder is slidably mounted, and I I the feed-screw, of arock-drilling engine. The d rill-feeding mechanism comprises the screw II, the operating-handle O, the flange P, and a washer Q, which bearsagainst a shoulder R, formed on the screw. The screw is also providedwith a collar S, which projects into a recess T, formedin the flange.This collar takes the. backward thrust of the screw. The handle O isscrewed against the washer Q, which bears against the shoulder R, andthe round portion U of the screw, between the shoulder and the collar,is made a little wider than the surrounding bearing of the flange, sothat the screw can rotate freely in the flange. On the end of the screw,beyond the handle, I screw a nut V tightly against the handle. Thefeed-screw-supporting flange P is provided with two oppositelaterally-extending ears R and S, by which it is bolted to the mainguide-shell of the drilling-en gine by the bolts T and T2. These boltspass freely through the ears and the flange V' of the guide-shell andare secured there by nuts V2 and NV, which are threaded to their endsand which are tightened against the side of the lugs and flange. Thefeedscrew is threaded through a nut X, which is rigidly supported in adepending lug Y, formed on the bottom of the cylinder D I). This nut isclamped in said lug by a nut Y. The cylinder is provided with a frontcylinder-head 2, which is threaded to the end of the cylinder. Thisfront cylinder-head contains an axial bore 3 in its front end, in whichfits a drill-bit-holding chuck-sleeve 4. The front cylinder-head alsocontains a counterbore 5 of larger diameter, which is bored into it fromits cylinder end a portion of its lengt-h, where it intersects a thirdcounterbore G,which is smaller in diameter than counterbore 5 andextends to and intersects counterbore 3. I place in the largecounterbore 5 a steel ring 7, whichI call a chuck-ringand which tits upagainstthe shoulder formed by the intersection of the counterbores 5 andt3. This chuck-ring forms a bearing for the chuck 8, which titsrevolubly inv it and also extends loosely into the chuck-sleeve. Againstthe inner ends of this chuck-ring I place a thin steel ring 9, andbetween this ring and the shoulder, at the intersection of the twocounterbores and tl, I place a coiled spring IO. The drill-bit-holdingchuck-sleeve tits slidably and rotatably in the smaller connterbore 3and extends out beyond the end of the cyliuder-head far enough to beclasped by the hand of an operator, and in order that the sleeve may beiirml y held by the hand the external surfaceislmurledoriluted.Thissleevc extends under the spring and under the adjacent edge ofthechuck-ring. The outer end of the chuck-sleeve is introverted to form anend tiange through which is formed an elongated hole 11. The opposite end of the chuck-sleeve extends toa shoulder 12, formed on the ch uck, andadjacent to this end a collar 13 is formed which fits in a rabbeted edge14, formed irl the inner peripheral edge of the ring 9. Between thecollar and the adjacent end of the chuck-sleeve the metal in the sleeveis cut away on opposite sides to leave two diametrically oppositeportions or spurs l5 and 15. Each of these spurs contains aboutone-quarter of the metal in the circumference of tlie sleeve and eacliextends axially and parallel with one an other from the collar. Theseprojecting spurs of metal are clearly illustrated in Figs. 2l and 23.They act as stops for the chuck-sleeve when a manual rotative movementis given the chuck-sleeve, which is necessary in order to lock thedrill-bit in place, as will be described more fully hereinafter. Thesespurs engage two diametrically oppositely disposed lugs 16 and 17, whichproject from the surface of the chuck 8, contiguous to the collar 13.The outer end of the chuck 8 contains a slot 1S, formed diametricallyacross its end, as shown in Fig. 24C. This chuck extends up to the endflange of the chuck-sleeve. The slot in the chuck and the elongated holein the end of the chuck-sleeve are formed to receive loosely the shank20 and the lugs 2l of the rock-cutting drill-bit 22. The slotin thechuck is made enough longer than the lugs on the drillshank to allow thedrill-bit about a half-inch longitudinal feed movement. be made withone, two, three, four, or more cutting-lips; butI preferablyusecross-sl1aped steel and make four cutting edges, as shown in Fig. 2. Theshank is preferably round, although other forms may be used. Thedrillbit is provided through its center with an axial hole 22d, or, ifpreferred, a closed conduit or a closed passage of any suitablecharacter may be arranged along its sides. As illustrated, a hole of twodiameters is shown. This is not necessary, as a hole of even diameterwill do. It is only necessary that the water-tube project very freelyinto its shank end. At a short distance from the end of its shank endtwo projectingdiainetrically oppositely arranged lugs 9.1 are formed.The end of the shank and these lugs are adapted to fit loosely in theoblong slots of the chuck-sleeve and chuck as they are inserted throughthe chuck-sleeve into the chuck; but in order to insert thein and the drill-shank into the chuck it is first necessary to turn the chuck-sleeveuntil its oblong hole comes in line with the oblong hole in the chuck.Then the d rill-shank can be inserted until its lugs occupy the slots inthe chuck. The chuck-sleeve is then turned at right angles to the slotsin the chuck, as shown in Figs. 9 and 27, at which points its spurs 15and lfL strike the projectinglugs 16 and 17 ofthe chuck. Thechuck-sleeve is arranged to be moved very freely in the cylinderhead andon the chuck at all times by the hand of the operator, so that adrill-bit mayr be taken ont and inserted at any time, and it turns withthe drill-bit as it rotates step by step when drilling rock, as will befully derlhe rock-cutting drill-bits may IOL IOO

scribed hereinafter. The 'chuck-ring 7 has aninverted flange at its endnearest the cylinder, which extends down over the end ot the chuck. Anoil-groove 24 is also cut around the periphery of the ring, and in thegroove through the shell several holes 25 are drilled, which allow theoil to flow to the chuck and its adjacentparts. This oil-grooveregisters with a hole 26, drilled through the overlapping ends of thecylinder-head and the cylinder. A cap-screw 26A is threaded to theentrance of the oil-hole. In the inner end of the chuck I thread a nut27, which contains an axial hole, in the peripheral wall of which I forma number of straight parallel flutes 28, through which reciprocallyslides the ham- 1ner-bar29 ot the piston. This hammer-bar is an integralpart of the piston, and its end is luted with straight parallel flutes28A to t freely in the flutes of the nut. Surrounding the hammer-barthere is a series of rings 3l, 32, and 33. The ring 3l is a rubberbuffer-ring and bears against the end ot' the chuck-ring, and the ring32, which is a metal ring, bears against the ring 3l. This ring containsa circumferential groove 34, from which holes 35 extend through theshell of the ring. This peripheral groove registers opposite a passageor port 36, formed in the internal pheriphery ot' the cylinder, andbisects a port 37, drilled axially through the top ot' the cylinder intothe port 38, which leads from the valve-chest and its ports into thecylinder. At the junction of the port 37 and 38 I place an automaticallyopening and closing valve 39, which Iarrange to normally keep the port37 closed. This valve comprises a tubular boss 39, extending upward fromthe cylinder. A cap 39D is threaded to the interior ot' the tube. Thevalve 40 consists of a stem 4l, containing an axial hole 42,extendinginto it to near its seat end. Its seat end is formed toregister against a seat formed in the cylinder in a position to controlthe port 37. A coiled expansion-spring 43 is placed in the stem4 of thevalve and between it and the cap and normally holds the valve closed. Iplace a steel ring 44 between the ring 32 and the ring 33, which is alsoa lnetal ring, and on each side of this steel ring I place acuppedwasher 45, made, preferably, ot leather, constructing them to bear onthe hammer-bar of the piston, cutting out the rings, so that they willlit snugly over the cupped washers and bear against the steel ring.These rings, with the rubber bufferring, fitin a counterbore in the endof the cylinder which is larger than the' piston-bore of the cylinder,and all these rings, together with the chuck-ring, arc pressed togetherbetween the shoulders of the counterbore of the cylinder andcylinder-head at the opposite ends of the group of rings when thecylinder-head is screwed onto the cylinder. The piston containscylinder-rings 4U near each end and atits centera circumferential groove47, Axially through the piston and its hammer-bar I drill a 4hole 48 oftwo diameters; The larger hole extends from the rear end of the body ofthe piston nearly through it and receives loosely the riled end of ariile-bar 49,which projects through a riiied nut 50, that is threaded inthe end of the piston. The smaller hole passes through the hammer-barand surrounds loosely a water-conveying tube 51. This tube also extendsloosely through therilie-bar. The rifle-bar contains a ratchetheadportion 49A at its end opposite the riiied portion, which is surroundedby three pawls 52. This rifle-bar 49, its pawls 52, which are shown inFigs. l and 8, the rear steel bufferring 53, and the rubber buffer-ring54 are supported in a supplementary cylinder-head 55, which isthrc'adedly secured in a counterbore in the rear end of the cylinder.This supplementary head contains a chamber in which the said rubberbutter is seated, and the steel ring is placed at its side at the bottomof the counterbore in the end ot the cylinder. The opposite side of thesupplementary cylinder-head is chambered ont to hold the ratchet-head ofthe rifle bar and the pawls. This rifle-bar and ratchet mechanism isused for turning the rock-cutting drill-bit through the medium of thepiston and adjacent parts and is in common use in rockdrilling enginesfor this purpose. Myinvention, however, contemplates the use of anysuitable ritle-and-pawl mechanism, although I preferably use that shownin Letters Patent of the United States No. 583,089. The supplementarycylinder-head 55 and the rear cylinder-head 56 have formed between theman annular recess in which is fitted loosely a fiat ring 57, in which Idrill three holes which form supporting-bearings for the adjacenttrunnions 59 of each pawl. Three pawls are used around the ratchet-headof the rifle-bar, substantially as shown in Fig. 8, and are used to lockthe rifle-bar against rotary movement in one direction, and coperativelywith the rifle-bar they operate to rotate the piston step by step as itreciprocates in the cylinder. An axial recess is also formed in the learcylinder-head around the tube 5l to support the hub 60 of theratchet-wheel. The rear cylinder-head 56 in Fig. l is threaded to acounterbore in the end of the supplementary cylinder, andit is necessaryin order to screw it on that the adjacent trunnions of the pawls have abearing independent of the cylinderhead and one that will remainstationary while the cylinder-head is being screwed into place. The rearcylinderhead comprises a flanged head portion with a round body portiona trifle longer than its diameter, which is axially bored out from itsouter end to form a valve-chamber. This valve-chamber is internallythreaded to receive a threaded plugvalve 61, which is provided with asmall hand- Wheel G2 at its outer end. Its inner end is pointed to fornia plug-valve, andthe bottoni of the valve-chamber is beveled to form aseat for the valve end of the plug. Axiallythrough IOO the valve-seat ahole 63 is drilled from the valve-chamber through the cylinder-head intothe water-tube, and the plug-valve is adapted to be screwed to and fromthe valve-seat and to control the passage from the valve-charnber to thewater-tube. A gland 64 is mounted on the plug-valve and is threaded tothe end 'of the cylinder-head, and packing '65 is placed in the gland toprevent the leakage of water by the valve. A shoulder '0G is formed by aportion that blends from the flange-head, which is larger in diameterthan the portion upon which the gland is mounted, and against thisshoulder, around the cylinder-head, is placed a washer G7. The washerillustrated preferably comprises a flat rubber ring covered with copper.At the side of the washer 07 I mount to turn freely a coupling 68, whichis provided with an annular chamber 00. Through the shell of thecylinder-head a hole is drilled into the valve-chamber and forms apassage from the coupling to it. At the sides of the coupling a washer71 is placed, anda nut 72 is threaded to the cylinder-head at the sideofthe said washer, which is adapted to be screwed against the washer tocompress the coupling and washers against the said shoulder and eachother tight enough to prevent leakage of the water from the coupling.One side of the coupling is provided with a projecting threaded nipple73, to which a hose 74 is secured. The hose connects the coupling withany suitable supply of water or with any suitable watery liquid underpressure enough to give the liquid operative power to eject the rockcuttings from the holes. By slightly loosening the nut 72 the couplingmay be turned on the cylinder-head, as indicated by the arrows 7 5,

so that the hose of the water-supply may be` connected to either side ofthe drilling-engine as required. I thread a cap-screw 7G in the end ofthe cylinder over the supplementary cylinder-head and drill thecap-screw hole into the supplementary head and also drill a second hole77 from the adjacent recess of the pawls trunnion to intersect it. Theseholes form an oil-passage to the pawls and ratchet. The oil placed inthem also works along the rifle-bar to the ride-nut in the piston-head.This nut is fluted to slide freely on the rifles 78 of the rifle-bar 49.A similar groove S0 is cut in the threads of the supplementarycylinder-head 55, which registers with the oil-hole in which thecap-screw 76 is threaded. The valve-chestF F has a cylindrical bore, andat its ends cylinder-heads S1 are threaded to it. These are providedwith a wrench-receiving hub, hy which the heads can be readily screwedon or from the valve-chest. The valve-chest is secured to the cylinderby the cap-screws 82.

My invention contemplates the use of any suitable form or type ot valveand any arrangement of valve-ports or exhaust-ports which, through themedium of any expansive fluid,will automatically operate the valve andpiston. I preferably construct the valve and ports, however, in thefollowing manner: The valve-chest F F contains a cylindricalvalvechamber, and a cylindrical valve G Gr is fitted snugly but looselyto it and reciprocates in it. The valve comprises a stem 81, whichcontains four collar portions S5, which vare so disposed as to coveroperatively a corresponding number of ports, which comprisecircumferential recesses formed in the valve-cham?- ber oli' the chest.The port S6 is an air-inlet port (see Figs. 1, 12, 13, 14, 15, and 16)and connects with the air-inlet boss 87, to which a pipe or hose leadingfrom a compressed-air supply is connected. The ports S8 and 80 lead toopposite ends of the cylinder. The ports 90 and 91 are exhaust-ports andconnect with the outlet-holes in the dischargebosses 02,1rom which theair discharges. At opposite ends of the valve-chest small holes 03 and04 are drilled through its seat portion on the cylinder from its valvechamber. These holes connect with recesses 05 and 90, milled in thesurface of the valves seat on top of the cylinder. These recesses extendfirstdown the center of the seat and then branch ott at right angles tonear the edge of the seat and then turn and extend parallel with theaxis of the cylinder. They turn in opposite directions from the center;but at `the second turn they extend longitudinally along the seat in thesame direction. Their exact position is not very particular, they beingplaced in the path of the circumferential groove in the center of thepiston, so as to let the air out of the ends of the valve-chest. In therecess 95 there are two holes 07 and 98 (see Figs. 17 and 20) at aboutseven-sixteenths of an inch apart. These are placed beyond the end ofthe adjacent main cylinder-port. Adjacent to these two holes a thirdhole 08A is drilled, which does not extend through into the cylinder,but acts as a keeper of a pin 09, which lits loosely in it. The recess96 contains a hole 100, which extends into the cylinder. The valvecontains holes 101 and 102 in each end, both of which extend inside thetwo central collars, where small holes 103 and 104C are drilled throughthe stem into the end holes.

105 is an exhaust-hole in the valve-chest.

106 designates a recess milled in the seat. It is placed between themain cylinder-ports and has two right-angled Ls,that pass around theports, in the end of which there are holes 107 and 108, drilled int-othe cylinder. These holes also lie in the paths of the circumferentialgroove in the center ot' the piston as the piston recprocates. Theexhaust-hole 105 lits over either one end or the other of this recess,depending on which way the valve is set on the cylinder, as it is madeto be reversed end for end.

The operation of the valves and ports is as follows: The air enters thecenter ol' the chest between the center collars of the valve and is freeto flow to the ends of the valve IOC IIO

through the holes that lead through the stem to them. Consequently ifthe piston is in a position to cover both holes 97 and 100 the valve isbalanced; but the air leaks through the holes 93 and 92 and through therecesses 95 and 96 and holes 97, 98, and 100 and flows to thecircumferential groove around the piston and from it flows throughwhicheverone of the holes 107 or 10S the pistons groove is nearest tointo the recess 106, from which it flows through the hole 105 to theatmosphere. This action relieves the pressure of air from one end on theother end of the valve, and the pressure on the opposite end causes itto move its stroke in one direction in the cylinder. The two holes 97and9S in the recess 95 are used to give two different strengths of blows tothe piston. 'lhus when the pin is taken out of its keeping-hole andplaced in the hole 97 this hole is closed, and as the hole 98 is nearerto the end of the cylinder and the farthest from the piston-groove thepressure 011 the adjacent end of the valve is not relieved as quick asif the hole 97 were open. Consequently the piston is not cushioned butslightly and travels practically its full strokeand consequentlystrikesaharder blow forward.

The operation of my improved rock-drilling engine is as follows: Theactuating fluid is admitted to the valve-chest F F and to the valve andoperates through the medium of the cooperating ports in the valve andchest and cylinder to automatically reciprocate the valve in the chestand the piston in the cyl'- inder in a well-known manner. The piston isturned step by step asit is reciprocated by sliding spirally on therifle-bar, which is held against turning in one direction byits pawls.'lhe piston as it reciprocates strikes with its hammer-bar on the end ofthe drill. The drill-bit and drilling-engine should be fed by theoperator through the medium of the feedscrew l I to keep the cutting endof the drill against or close to the rock. The drill and rock receivethe full force of the blow of the piston and its hammer-bar. The recoilof the drill-bit from the blow of the piston will move it back a slightdistance from the rock, where it can be easily turned stepbystep throughthe medium of the piston, the rifle-bar, the tinted hammer-bar of thepiston, and the fluted nut and chuck, for the piston turns the flutednut and chuck, and the chuck turns the drill cutting-bit. At each strokeof the piston a portion of the air that iiows through the front port 38raises the automatic valve and flows through the port 37 and ring 32 tothe flutes of the hammer-bar of the piston and through the tinted-nutinside the chuck and around the water-tube into the end Iof thedrill-bit, where it mingles withthe water. The water should preferablybe under pressure enough to flow to and through the drilling-engine anddrill-bit without causing back pressure on the actuating fluid minglingwith it. The watersupply pipe or hoseis connected to the couphlikesections of air as they both Iiow along.

The water flows in a steady stream; but the size of the stream can beregulated, and preferably is so regulated by the plug-valve, and can bereduced to a size that when mingled with air will result in a spraywhich is discharged in pu ifs from the drill-bit in the bottom of thehole immediately after each blow of the piston'against the drill-bit andof the drill-bit against the rock and allays the dust as well as drivesthe rock-cuttings from the hole. Some kinds of rock will require morewater than a spray would give, but anyamonnt of water can be combinedwith the air and may be discharged in a steady stream if necessary, asits volu me can be regulated by the plug-valve. The reciprocative actionof the piston and its hammer-bar and the intermittent exhaust of the airfrom the front end of the cylinder has a tendency to draw a little waterinto the cylinder on the back stroke of the piston bysuction,especiallyas the water flows steadily into the drill-bit; but the cupped washersmaintain an operative water seal around the hammer-bar of the pistonsufficiently tight to keep any harmful quantities of water out. Thevalves and ports are arranged so that when the drill is running thepiston will cushion on its rear stroke on air without striking the rearring; but the piston strikes the front ring 33 when a drill-bit is notin the chuck. The blows on the ring 33 have the effect of keeping thecupped washers bearing snugly around the hammerbar. A harmful quantityof water in the cylinder carries off the lubricating-oil and weakens theblow of the piston as well as aln lowing the piston and cylinder to wearfaster. When the point of the drill-bit is not in operative strikingrelation to rock, the pistons hammer-bar strikes against the end of thedrill-bit and drives it forward in the chuck until its lugs strike theend flange of the chuck-sleeve and the eh nek-sleeve jumps forward undereach blow; but as the collar on this sleeve is connected to the ring atthe end of the coiled spring the ring and spring are also moved forwardby the blows on the shank of the drill-bit, and the spring is compressedand the blows are thus cushioned. Consequently no severe blows arestruck by the piston against the ring nearest the cupped washers. When,however, the drill-bit is against or close to rock in drilling, thecylinder is fed by the feed-screw to keep the lugs of the drillbit froma quarter to one-half inch from the iianged end of the chuck-sleeve.Then the blows of the piston will drive the drill-bit against and intothe rock, and if the cylinder is fed properly there will always be ampleclearance between the lugs and the flanged end of the chuck-sleeve.

My invention contemplates a controllable supply of water under pressureiiowing to the cutting-point of the drill-bit. In practice I use a smalltank. One of about eighteen gallons capacity is large enough for eachdrill.

I place this tank at a convenientdistance from A each drill and keep itwell supplied with water and connect it direct with the air-compressoror air-supply system and also connect the tank to the drilling-engine byhose-pipe. The rock-cuttings are a source of great aunoyance in drillingrock, as they clog the drillbit and strain the turning mechanism ot' thedrill-bit. They also prevent by packing between the cutting-point of thedrill and the rock the drills cutting as fast as it would if they wereremoved. 'lhe cutting edge of a drill will also wear longer it the holeis kept free from cuttings. All rock-drilling engines at present in useare of the type known as plunger drillingengines. They derive thisnamefrom the fact that the drill-bits are removably clamped or bolted orotherwise tightly secured to an extension of the pistonhead called theplu nger, which extends through and beyond the cylinder and reciprocatesthrough it and is reciprocated and impinged by the piston against therock, and it is necessaryin a I ilunger-drill every time therock-cuttings are removed from a hole being drilled to move thedrill-bitout ot alinement with the hole in orde'r to insert aspooningtool to remove them and afterward to reset and clamp the drill-bit in line with the hole. By my present invention I am enabled tochange lhedrill-bits very quickly,as they rest loosely in the sleeve. Iam also enabled in my new type of drilling-engine, first, to save `timein changing drill-bits; second, to cl'i'ect a saving in the wea-randfdressing of the drillbit; third, to get a more eiectiveblow on thedrill-bit from the piston; fourth, to cut as large a' hole and cut it asfast or faster willi fully fifty per cent. less air than a plungertypedrilling-engine of the same-sized cylinder. My new type ofdrilling-engine strikes about twelve hundred blows per minute and weighsabout one-half as much as a plungertype drill ot' similar-sizedcylinder.

Vhile I have illustrated and described my preferred method and apparatusfor expellingrock-cuttings from holes while drilling them, I do not wishto be limited to the construction and arrangement shown,.but claim theright to use any and all arrangements by which a portion of arock-drillin g engines actuating fluid and a supply ot water or awatery' liquid is conveyed to or adjacent to the cutting-point of thedrill-bit and to the bottoln of holes in rock while drilling them.

Having described my invention, what I claim as new, and desire to secureby Letters Patent, is`

1. In a rock-drilling engine, the combination with the cylinder and thepiston, of a front cylinder-head comprising an integral, cylindricalmember adapted to be threaded to the end of said cylinder, an axial borethrough said head, a counterbore at its inner end, a chuck-bearing ringrotatably seated in said bore, and a drill-holdin g chuck rotatablymounted in said chuck-ring, substantially as described.

2. In a rock-drilling engine, the combination with the cylinder, thepiston and the cylinder-head, of a rotatable chuck-ring, axiallysupported in said cylinder-head, and a drillholding chuck supported bysaid chuck-ring, with a rock-cutt ing d rill-bit loosely supported insaid chuck, and having the shank extending into said chuck and adaptedto be impinged by the reciproeative movementot the piston, substantiallyas described.

3. In a rock-drilling engine the combination with the cylinder, thepiston and the front cylinder-head having an axial bore, ot' acounterbore adjacent to its cylinder end, a chuck-ring in the largerbore ot said cylinder, a second eounterbore intermediate ofthe otherltwo eounterbores, a steel ring bearing against the outer end of saidring, a spring between said ring and a shoulder formed in saidcylinder-head, a drill-holding chuck rotatably mounted in saidchuck-ring; a drill-bit adapted to be held loosely by said chuck, and achuck-sleeve in said cylinder-head adapted to be manually turned to locksaid drill-bit loosely and removably to said chuck, substantially asdescribed.

4. In a rock-drilling engine the combination with the cylinder and thepiston, of the front cylinder-head, the chuck-ring therein, the chucksupported by said chuck-ring; the chuck-sleeve surrounding the chuck andextending beyond thcend of said cylinder-head far enough to be turned bythe hand ol an operator, the spring and the spring-ring substantially asdescribed.

5. In a rock-drilling engine the combination with the cylinder and thepiston, of the front cylinder-head, the chuck therein, the chuck-ringfor supporting the same; a luted nut in the end of said chuck, ahammer-bar forming an extension of said piston and having a luted endfitting the iluted nut in said chuck; a drill-bit loosely supported bysaid chuck and extending' into the reciprocating path ol said piston andmeans for manually locking and for unlocking said drill-bit to and fromsaid chuck, substantially as described.

G. In a rock-drilling engine the combination with the cylinder and thepiston, of the front cylinder-head, a drill-holding-ehuck rotatablysupported axially therein', a drill-bit operatively supported by saidchuck, means for manually locking said drill-bit to and for unlocking itfrom said chuck and means connected with the said piston for rotating orturning said chuck and drill-bitstep by step, substantially asdescribed.

ICO

IIO

'7. In a rock-drilling engine the combination with a cylinder, a piston,a valve-chest and valve and a front cylinder-head, of a rockcuttingdrill-bit having an axial hole through it from end to end; aWater-conveying tube extending into said drill-bit and arranged andadapted to deliver a supply of Water under pressure; a supply of airilowing from said valve-chest to said drill-bit and mingling With andflowing with said water to the bottoms of holes in rock While drillingthem, and an automatically opening` and closing valve arranged andadapted to be opened and. closed by the pressure of the air and to allowonly asuitable amount of air to flow to the drillbit, to eject, whencombined with said Water, the rock-cuttings from the hole heiligdrilled, substantially as described.

8. The combination in a rock-drilling engine vof the cylinder, thepiston, the front cylinderhead and the drill-holding chuck andchucksleeve with a drill-bit adapted to be operatively supported by saidchuck and chucksleeve and havingashank and two oppositelyarrangedprojections formed on said shank near its end and an axial perforationthrough said drill-bit and means connected with said chuck andchuck-sleeve for rotating said drill-bit step by step, substantially asdescribed.

9. In a rock-drilling engine the combination of the cylinder, thepiston, the cylinderhead, the chuck-ring mounted in said cylinder-head,and the chuck and chuck-sleeve, with a drill-bit of any form ofcross-section, having a striking end adapted to fit freely in said chuckand arranged to be operatively impinged by and intermittently rotated bysaid piston, a projection at substantially diametrically-oppositepoints, adjacent to said drill-points striking end, adapted to looselylock said d rill-bit rotatably to said chuck and against longitudinaldisplacement from said chuck and chuck-sleeve, and a passage or conduitfrom the striking end of said drill-bit to its cutting-point adapted toconvey a portion of the pistons actuating fluid from said cylinder tothe cutting-point of said d rill-bit and to the bottom of the hole beingdrilled, substantially as described.

10. In a rock-drilling engine a rock-drill bit having a drill-shank ofany merchantable form of cross-section and having a cuttingpoint of anydesired common form, a shank end adapted to be struck by said piston; alug or shoulder adjacent to said end and an axial hole from end to endthroughout its length, or a closed passage attached to or arranged toform a part of said drill-bit extending from its striking end to itscut-ting-point,`

substantially as described.

ll. In a rock-drilling engine a rock-cutting drill loosely positionedand supported in the drilling-engine and arranged to be iinpinged uponone end by a reciprocal movement ot` the piston, an axial hole throughsaid rockcutting drill from end to end arranged and adapted to convey aportion of the pistons actuating Huid directly from the cylinder to itscutting-point to blo7 out from the hole being drilled the rock-cuttings,and means for mingling a supply of Water with .said actuating fluid insaid rock-cutting drill, substantially as described.

12. In a rock-drilling engine for expellingrock-cuttings from holeswhile drilling them, consisting of an operative drilling-engine havingrock-cutting drills arranged and adapted to extend into the eylinderofthe drilling-engine and to be struck and actuated to cut rock by thereciprocative movements of the piston im pingi ng against its inner endand in which the cutting-drills have an axial .hole through them fromend lo end, and the pistons actuating uid is controllably suppliedautomatically to the axial hole in said rock-cutting drill, and meansfor leading a supply ot' Water under pressure into the axial hole insaid drill-bit and for mingling the air and Water together and fordischarging them in the bottom of holes in rock while drilling them,substantially as described.

13. In a rock-drilling enginearock-cutting drill arranged to be struckby the reciprocal movements of the piston, and provided with a collar,projection, or shoulder adjacent to its striking end, adapted to form alocking, securing and positive means for holding and rotating saiddrill-bit, and a passage axially through said cutting-drill arranged toconduct a portion of the pistons actuating fluid from the cylinder tothe cutting-point of said rock-cutting drill, anda valve for controllingthe supply ofactuating fluid flowing to the drill-bit, substantially asdescribed.

let. In a rock-drilling engine a drill-bit arranged to projectinto thecylinderof the drilling-engine and arranged to be operatively struckupon its end by the reciprocal movements of the engines piston andcontaining a passage or conduit'from said engines cylinder to oradjacent to said drill-bits cuttingpoint and a Water passage or tubethrough said drilling-engine to said passage in said drill-bit, means toprovide a suitable Watersupply for said passage and said' drill-bit,whereby a com mingled supply of the cylinders actuating iiuid and Wateris conveyed from said drillingengine through said drillbit to itscutting-point and to the bottom of holes in rock While drilling them,substantially as described.

l I5. In a rock-drilling engineasuitable cylinder, a reciprocativepiston, a suitable controlling-valve and suitable feeding mechanism anddrill-bits arranged to project into said cylinder into the reciprocalpath of said piston and arranged an d adapted to be struck directly ontheir cylinder-invading ends by the reciprocal movements of said piston,and containing a passage or conduit for the actuating tluid of saidrock-drilling engine, opening into or communicating With said enginescylinder and exten ding through said drill-bits IOO IIO

to or adjacent to their cutting-points, a waterconveying tube or conduitconnecting with the said passage or conduit in said drill-bits, means toprovide a suitable water-supply and to mingle with it a portion of theeylinders actuating iluid, substantially tts-described.

1G. In a rock-drilling engine, the combination of the cylinder, thepiston, the cylinderheads, the chuck-sleeve, the chuck and the hollowdrill, with a liquid or water conveying tube through said pistonconnected with said hollow drill and a valve-con trolled passage fromsaid cylinder adapted to allow a suitable supply of the cylindersactuating lluid to flow into said hollow drill, whereby a combinedstream of liquid and actuating iiuid is caused to flow through saiddrill-bit to the bottom of holes while drilling them, and means,includinga valve, for controlling the volume and pressure of said liquidand actuating-Huid stream, substantially as described.

17.` In a rock-drilling engine the combination With the cylinder, of apiston having an extension hammer-bar, the front cylinderhcad, thechuck-sleeve, the chuck, the chuckring and the cupped washers and ringssurrounding said hammer-bar, with a hollow drill-bit held loosely bysaid chuck-sleeve and chuck, and arranged to be instantly withdrawn fromor inserted in said chuck-sleeve and chuck, and provided with means fordeiining its operative position in said chucksleeve and chuck and tosaid cylinder and piston and with a fixed tube projecting from the rearend of said cylinder freely through said piston and extending-intosaid-drill-bit, substantially as described.

1S. In a rock-drilling engine the combination with the cylinder and thepiston, of a hollow drill-bit projecting into said cylinder into thereciprocating path of the piston and arranged to convey a port-ion ofthe pistons actuating fluid to the bottom of holes while drilling them,with a water-tube projecting into said drill-bit for supplying waterunder pressure and mingling it with the actuating iiuid of saiddrill-bit and discharging into the bottom of holes while drilling them acombined stream of actuating iiuid and water, and means for preventingthe water from entering said cylinder, substantially as described.

19. In a rock-drilling engine the combination with the piston, thecylinder and the valve and chest, of the drill-bit, the supplementarycylinder-head, the ride-bar and the rear cylinder-head having awater-inlet tube secured thereto and projecting therefrom looselythrough the axial center of said riliebar and said piston into thestriking end of said drill-bit, and an actuating-fluid passage leadingfrom the valve-chest and cylinder to said drill-bit, substantially. asdescribed.

l20. In a rock-drilling engine, the combination with the drill-bit, thecylinder, the valvechest and valve, the piston and the ride-bar,

axial holes through said ride-bar and piston, a ,water-inlet tubeprojecting loosely through said axial holes into said drill-bit adaptedto conduct a stream of water under pressure through said tubes anddrill-bit, a valve for controlling the fiow of said water, and avalvecontrolled actuatingfluid passage leading from said valve-chest andcylinder into said drill-bit and means for preventing a harmful flow ofwater into said cylinder, substantially as described.

2l. In a rock-drilling engine, the combination of a piston having ariiie-bar, a drill-bit having an axial hole through it, a cylinderhaving a water-conveying tube projecting through said ride-bar andpiston into said drill-bit, a water-passage to said tube, a valveadjacent to said tube for controlling said passage, means for minglingsaid water with a,

portion of the engines actuating iiuid, means for conducting saidactuating iiuid and water in a combined stream to the bottom of holes inrock while drilling them, and means for i preventing a harmful flow ofwater into said cylinder, substantially as described.

In a rock-drilling engine the combination with the hollow drill-bit, ofthe chucksleeve, the chuck, the cylinder; the piston, having a hammer-bar extension; the rifle-bar and the rear cylinder-head having awaterinlet tube projecting through said rifle-bar and piston into saiddrill-bit, a passage around said tube from said'cylinder into saiddrillbit, and means, including cupped Washers arranged to surround thepistons hammerbar for preventing a harmful iiow of Water into saidcylinder, substantially as described.

In a rock-drilling engine, the combination with the cylinder and thepiston, of a hollow drill-bit mounted to be turned step by step by saidpiston, a Water-inlet tube projecting into said drill-bit and avalve-controlled actuating-fluid passage from said cylinder into saiddrill-bit, substantially as described.

24. In a rock-drilling engine the combinationwith the cylinder, thepiston, the cylinder-head and the sleeve, of a hollow drill-bitprojecting into said cylinder, means for conveying a portion of thecylinders actuating fluid to its cutting-point, of a conduit adapted toconvey a stream of water under pressure to said drill-point, a rearcylinderheada passage in said cylinder-head for said water, a valveadapted to control the admission and volume of said water, and awater-inlet coupling adapted to connect with a source of water-supply oneither side of said cylinder, substantially as described.

25. In a rock-drilling engine the combination with the piston having anaxial hole, the drill-bit, the ride-bar havingan axial hole and the backcylinder-head carrying a Waterinlet tube projecting through the axialbores of said rilie-bar and piston, with a water-inlet couplingrotatably mounted on said cylinder-head, a passage from said coupling toIOC IIO

said tube and means, including a nut and thread for packing saidcoupling against leakage, substantially as described.

26. In a rock-drilling engine, the combination of the hollow drill-bit,the piston, the rifle-bar, and the back cylinder-head, with a tubeprojecting loosely through bores in said rifle-bar and piston and with aWater-inlet coupling having a hoseor pipe connecting nipple, and apassage from said coupling to said tube, substantially as described.

27. In a rock-drilling engine, the combination with the backcylinder-head, of the rotatable water-coupling mounted thereon, ashoulder or abutment adjacent to said coupling, a Washer between saidcoupling and said shoulder, a second washer on the opposite side of saidcoupling7 and a nut threaded to said cylinder-head adapted to tightensaid washers and coupling against said shoulder and thereby pack saidcoupling against leakage, substantially as described.

2S. In a rock-drilling engine, the combination of the supplementarycylinder-head, the rear cylinder-head secured thereto, the Waterinlettube, the rifle-bar revoluble on said tube, the piston arranged toreciprocate and turn on said tube and the hollow drill-bit surroundingthe discharging end of said tube, substantially as described.

29. In a rock-drilling engine, the combination with the backcylinder-head of the Waterinlet coupling rotatively mounted thereon, thewasher at its sides and the tighteningnut, substantially as described.

30. In a rock-drilling engine, the combination with the cylinder, of thepiston, the hollow drill-bit, the ride-bar and the Water-inlet tubeprojecting through said rifle-bar and piston into said'drill-bit, withthe back cylinder-head, the Water-inlet passage therein; the water-inletcoupling and the valve for controlling said water-inlet passage,substantially as described.

31. In a rock-drilling engine, the combination of the cylinder, thepiston, the rifle-bar and the pawls, with the supplementarycylinder-head and back cylinder-head, the pawltrunnion-supporting ring;a water-inlet tube, a threaded hole in said cylinder and into saidsupplementary cylinder-head; a cap-screw in said threaded hole and anoil-hole leading from said cap-screw hole to said pawls and rifle-bar,substantially as described.

32. In a rock-drilling engine, the combination of the cylinder and thepiston, with the front cylinder-head having a drill-holding chuckrotatably mounted therein, and arranged to be turned step by step bysaid piston, a drill-bit operatively supported by said chuck andarranged to conduct a portion of the cylinders actuating fluid and astream of water from the engines cylinder to its cutting-point, achuck-sleeve surrounding said chuck, a collar on said chuck-sleeve, aring mounted on said collar, a spring between said ring and an abutmentin said cylinder-head,

and means whereby the ring may be moved by the collar of saidchuck-sleeve to compress said spring, substantially'7 as described.

33. In a rock-drilling engine, the combination of the cylinder, thepiston and the front cylinder-head, a rock-cutting drill-bit havingprojections near the end of its shank, a drillbit-supporting mechanismconsisting ot' a chuck comprising a cylindrical tube containing twooppositely-arranged slots in its forward end, a liuted axial hole in itsopposite end, a hammer-bar extension to said piston, a uted portion atits end itting loosely in said iiuted end of said chuck, projections onsaid chuck, means for rotatably supporting said chuck in saidcylinder-head, a chucksleeve surrounding freely said chuck; stops onsaid chuck-sleeve arranged to engage said projections of said chuck, anend lange eX- tending over the end of said chuck, and an oblong holeaxially throughthe flanged end of said sleeve-chuck, adapted to fitloosely said drill-shank and lugs, substantially as described.

34. In a rock-drilling engine the combination of the cylinder, th'episton, the front and rear cylinder heads, the rifie bar rotatingmechanism and the feed mechanism, with a water-conveying tube projectingfrom the rear cylinder-head through said rifle-bar and piston, adrill-holding chuck and chuck-sleeve, revolubly mounted in saidcylinder-head; an axial bore through said sleeve and chuck, a

drill-bit'operatively supported by said sleeve' and chuck, and arrangedto be operatively rotated step by step by said piston and chuck, andprovided with a conduit or passage communicating with said cylinder andwith the discharge end of said water-conveying tube and arranged andadapted to convey a combined and commingled stream of water andactuating fluid to the cutting-point of said drill-bit, and having saiddrill-bit project into the reciprocal path of said piston and arrangedto be impinged by said piston, a collet loosely mounted on saidchuck-sleeve, a ring mounted on said collet, a spring arranged betweensaid ring and an abutment in said cylinder-head, substantially asdescribed.

35. In a rock-drilling engine, the combination of the cylinder, and thefront cylinderhead, of a piston in said cylinder having an extended baradapted to strike on the shank end of a rock-cutting drill-bit and aseries of flutes cut around said bar, a drill-holding chuck mountedloosely on the fluted portion of said bar, a rock-cutting drill-bit,means for removably securing said drill-bit to said chuck, and means'forrotating said piston tially as described.

36. In a rock-drilling engine, the combination of the cylinder and thefront cylinderhead, with a rock-cutting drill-bit, a drillholding chuck,arranged to hold the drill loosely and in such a manner that it can beinstantly inserted or removed from said chuck,

IOO

IIO

`and chuck and rock-cuttin g drill-bit, substanmanually, a piston insaid cylinder having a hammer-bar extension adapted to strike the shankend of said drill-bit, means for rotating said piston step by step andmeans for rotating said drill-bit step by step from said piston,substantially as described.

37. In a rock-drilling engine the combination of the cylinder and thecylinder-head, with the manually-operatin g drill-bit-holding chuck, apiston having a hammer-bar extension; cupped washers mounted on saidhammer-bar, a ring between said cupped washers, a ring on the outside ofeach cupped washer, a rubber buffer-ring at the side of one ring andmeans for compressing the cupped washers around said ham mer-bar,substantially as described.

38. In a rock-drilling engine the combination of the cylinder and thedrill-bit manually-operating chuck, the piston arranged to strike saiddrill-bit; means for rotating said piston and drill-bit and meansincluding a spring for cushioning the blow of the piston on thedrill-bit when the drill-bit is out of cutting relation to rock,substantially as described.

39. In a rock-drilling engine the combination with the. cylinder, thepiston and the front cylinder-head, of the hollow drill-bit and thedrill-chuck and sleeve, means including a ride-bar for rotating saiddrill-bit step by step, means including a hand-operating device forsecuring said drill-bit instantly to or for removing it instantly fromsaid drill-holding chuck, means including a spring for cushioning thespent blow of the piston against said drill-bit, means including Vawater-conveying tube and a water-supply system under pressure fordelivering a supply of water into said drill-bit, means includingair-passages for delivering a suitable supply of actuating iiuid intothe water and in said drill-bit, means including packing-rings forkeeping the water out of said cylinder and means for operating andoiling the moving parts of said drilling-engine, substantially asdescribed.

40. In a rock-drilling engine, the combination with the cylinder, thepiston and its eX- tending hammer-bar, of the riiie-bar and pawls, andvalved water-conveying tube, the water-inlet coupling, the cylinder-headand the drill-holding chuck members arranged to be rotated by saidpiston, the hollow drill-bit supported by said chuck mechanism, theValve controlled actuating fluid passages leading to said hollowdrill-bit, the bufferring and the cupped washers and theirsupporting-rings surrounding said hammer-bar, substantially asdescribed.

41. Ina rock-drilling engine the combination with the cylinder and thepiston, oi' the front cylinder-head, the drill-holding chuck andchuck-sleeve, the drill-bit having the projecting lugs, the slots in thechuck in which said lugs are confined, and the end flange on thechuck-sleeve for confining the lugs to the slots of the chuck,substantially as described.

42. In a rock-drilling engine the combination of an operative cylinder,an operative valve mechanism, a piston arranged to rotate step by stepas it reciprocates in said cylinder and a suitable feed. mechanism, witha drill-bit loosely and unclampably supported operatively by saiddrilling-engine and arranged to be im pinged against by said piston, andadapted to be rotated step by step by said piston, and containingapassage throughout its length, passages controlled by anautomatically-operating valve, arrangedto convey a portion of thepistons actuating fluid into said drill-bit, a valved water-conveyingtube extending through said piston, means for providing a supply ofwater under pressure to said tube, and communicating with the passage insaid drill-bit and means for excluding the water from said cylinder,substantially as described.

43. In a rock-drilling engine the combination with the valve-chests, thevalve and the cylinder, of the piston having a circumferential groovecentrally of its length, actuatingfluid ports leading from saidvalve-chest to the ends of said cylinder, open passages leading from themain air-inlet port of said valve to its opposite ends, ports orpassages leading from the opposite ends of said valve-chest to aposition in the cylinder where they will register with the said annulargroove in said piston during its reciprocative movements, and having theport contain independent passages placed at a short distance apart andmeans for closing the passage nearest the center of the cylinder, andports leading from the path of travel of the central part of said pistonto the atmosphere, substantially as described.

4i. In a rock-drilling engine the combination with the valve-chest andvalve and the cylinder of ports arranged to coperate with the reciprocalmovements oit' the piston and with a circumferential port therein toautomatically operate and cushion the piston and means comprising twoseparated outlets leading into said cylinder, from the front port ofsaid cylinder, a pin for closing the port nearest the center of thecylinder and a hole in the cylinder in which to keep the pin when indisuse, whereby the opening of the valve in the forward or striking-blowend oi t-he `piston is retarded and a harder blow is struck,substantially as described.

45. In a rock-drilling engine the combination of the valve-chest, thevalve, the cylinder and the piston, of a circumferential groove aroundthe piston slightly near its forward or drill-striking end, portsleading from said valve-chest into said cylinder and from said cylinderto the atmosphere, and arranged to automatically operate the valve andpiston, and means comprising two independent and separate outlets forthe port leading into the front end of the cylinder, and means at theIOO TIO

IZO

control of the operator for closing the outlet of these two outlets ofthis port that is positioned nearest to the center of the cylinder,whereby two dierent strengths of blows may be struck by the piston atthe will of the operator, substantially as described.

4G. In a rock-drilling engine, the combination with the cylinder, thecylinder-head and the piston, of a drill-bit arranged to be struck bysaid piston and having lugs, shoulders or projections adjacent to itsshank end, a drillholding chuck containing an axial bore adapted toreceive the shank of said drill-bit and lateral recesses radiating fromsaid bore adapted to receive the lugs of said drill-bit; a sleeverotatably mounted on said chuck and extending beyond the end of saidcylinderhead far enough to be grasped by the hand of an operator, andcontaining a anged end extending down over the Vend of said chuck; anoblong aperture in the end of said chucksleeve arranged to admit theshank and lugs of said drill-shank to pass through said ange Ill intosaid chuck, when said chuck-sleeve is manually turned to bring itsdrill-shank-receiving aperture in line with the chucksdrill-shank-receiving aperture and having said chuck-sleeve arranged tobe partially rotated manually on said chuck after the drillshank isadmitted to the chuck to a position in which its drill-shank-receivingaperture will stand .crosswise or at substantially right angles to thedrill-shank-receiving aperture of the chuck, and means including stopso1' abutting surfaces for locking said chucksleevesdrill-shank-receiving aperture in its crossed or right-angled positionrelative to the drill-receiving aperture of said chuck, substantially asdescribed.

In testimony whereof I affix my signature in presence of two Witnesses.

JOHN GEORGE LEYNER.

Witnesses:

C. A. LAwsoN, JESSE Dirson.

